Granulating machine

ABSTRACT

A granulating mill having a cutter which is rotatably disposed in a granulate container. Pieces of material to be comminuted are supplied to the granulate container from a collection hopper. The cutter has shaft ends which are rotatably mounted on a centrally disposed subframe, which is itself pivotably mounted on a main pivot shaft attached to a main frame. The cutter and collection hopper are mutually pivotable about a first pivot, and the granulate container is pivotable about a second pivot. In addition, the cutter, collection hopper and granulate container are pivotable about the main pivot shaft via the subframe. Thus, by this arrangement, the cutter, collection hopper and granulate container require only minimal force for such components to be pivoted into position for servicing and cleaning of the granulating mill.

The present invention relates to an arrangement in granulating mills andincludes a cutter means with a cutter rotatably mounted in a granulatecontainer and disposed such that during rotation of the cutter theperimeter of its blades is juxtaposed to a cylindrically shaped sievemade from a perforated sheet of material and removably mounted in thecontainer, the perimeter also being accessible to an upper feed openingfor the shaped pieces of primarily plastics material that is to becomminuted, this material being supplied to the feed opening from acollection hopper situated above the cutter blades, which are adaptedfor coaction with at least one cutter bar disposed in the fixed part ofthe cutter means for comminuting the plastics material. The shaft endsof the cutter are journalled in bearings in a centrally disposedsubframe, which is in turn pivotably mounted via a main pivot shaftjournalled at either end in mutually opposing main pivot bearings fixedto the primary frame of the mill. The arrangement also includes a highpressure pump for conveying air through a first hose into the lowerportion of the container and for conveying the ready milled granulatevia a second hose away from the container to a collection point outsidethe mill.

A problem burdening already known granulating mills of a similar type isthat service and cleaning in connection with changing pigment or othermaterial are troublesome and time-consuming, as well as being verylaborious, since the components included in the mill have considerableweight, which comes into prominence in the dismantling necessary to getat the mill components which are to be serviced, exchanged or cleaned.It is important that cleaning is carried out very thoroughly whenchanging pigment or other material, since pieces or granules from aprevious comminuting operation with the mill can otherwise loosen anddiscolour the granulate in a subsequent operation.

The object of the present invention is thus to achieve an arrangement ingranulating mills of the kind mentioned in the introduction, where bothservice and cleaning in connection with changing pigment or othermaterial are substantially facilitated. The distinguishing featuresrequired for the invention are disclosed in the accompanying claims.

By reason of the invention there has now been provided an arrangement ingranulating mills of the kind mentioned above, and which excellentlyachieves the inventive intention, while being at the same timerelatively cheap and simple in its construction. The arrangement isunique in that all the chief components of the mill (excluding its mainframe) are suspended by a shaft, about which they pivot from a closedstate to an open state. Since the components are adapted such that theircommon centre of gravity has its line of action substantially passingthrough the shaft, this results in that these components will beapparently almost weightless during opening and closing the mill. At thesame time, after the mill has been opened by swinging apart thecomponents forming it, all the nooks and crannies of the apparatusbecome readily accessible for effective cleaning, this betteraccessibility ensuring that service can be performed more easily thanwith previously known arrangements. In addition, no special tools foropening up the mill are required, since the parts to be opened are kepttogether by bayonet-type latches, which can be rapidly opened. Thismeans that the entire service and/or cleaning procedure does not take along time, which is the case with known mill arrangements, thus enablingvery rapid, time-saving procedures. In connection with swinging ortipping the pivotable chief components of the mill to the open state,the granulate container opens automatically, and on termination of thetipping operation, a pivoting shaft for the upper components comprisingthe cutter and collection hopper, assumes a vertical position, whichenables swinging the collection hopper out laterally with the use ofpractically no force at all.

The invention will now be described in more detail below with the aid ofa preferred embodiment example, and with reference to the accompanyingdrawing, where:

FIG. 1 is a schematic side view of a granulating mill, arranged inaccordance with the present invention, in an operative, closed state.

FIG. 2 illustrates the mill of FIG. 1 in an open state, preliminary tocleaning and/or service.

FIG. 3 is a partial, schematic, perspective view of a part of the millarrangement in accordance with the invention, more specifically a highpressure pump in its swung out position, the pump being intended forconveying air through a supply hose, towards which the pump may be swungsuch that a sprung hose connection on the pump mates with the hose, and

FIG. 4 is a partial, schematic, perspective view of the mill, morespecifically the sprung hose connections for sealing engagement againstair input and output openings in the lower portion of the granulatecontainer.

As will be seen from FIGS. 1 and 2, the granulating mill 1, according toa preferred embodiment example of the invention, includes a main frame 4mounted on a carriage 2, which is movable with the aid of wheels 3. Theframe 4 carries a cutter 5 journalled for rotation in a granulatecontainer 6. The cutter is provided with blades 10, the periphery ofwhich during rotation is juxtaposed to a removable, semi-cylindricallyshaped sieve 7 of perforated sheet material, removably arranged in thecontainer 6. The mill also includes a collection hopper 9, and shapedpieces of primarily plastics material which are to be comminuted aresupplied via a feed opening 8 of the hopper 9, this opening being incommunication with the cutter 5. For comminuting the plastics materialthe blades 10 of the cutter 5 coact with at least one cutter bar 11situated on the fixed part of the cutter means, the cutter shaft ends 12of which are mounted for rotation by means of bearings 13, in turnmounted on a centrally placed subframe 14. The subframe 14 is pivotablymounted on a main shaft 15, in turn mounted in pivot bearings 16 rigidlyfastened to the main frame 4 of the mill 1. The latter also includes ahigh pressure pump 17 for conveying air in a first hose 18 into thelower portion 19 of the container 6 via an input opening 29, readymilled granulate being conveyed in a second hose 20 via an outputopening 30 in the portion 19 to a collection point outside the mill 1.

The cutter 5 and collection hopper 9 are mutually pivotable via means21, while the granulate container 6 is pivotable via means 22, thesecomponents being openably, mutually connected via unillustrated bayonetfastenings, and they are also pivotable about the main pivot shaft 15via the central subframe 14 carrying the cutter means. The line ofaction of the common centre of gravity of these components 5, 6 and 9substantially passes through the shaft 15, about which they arepivotable and balanced, whereby only minor force is required to swingthem into position for opening the mill 1 when service and/or cleaningare required in connection with changes in pigment/material.

As indicated in FIGS. 1 and 2, the pivot means 22 extends between thecutter 5 and granulate container 6 parallel to the main pivot shaft 15.When the unit formed by the cutter 5 and hopper 9 is swung about theshaft 15 to the open position, the granulate container 6 in the lowerportion of the mill is opened up as the container 6 moves about itspivot means 22. These movements reveal an opening plane formed by theupper edge of the container along an opening line 23 as the container islifted from a lower, closed position to its upper, open position.

The pivot means 21 between the cutter 5 and collection hopper 9 extendstransverse the main shaft 15. The result of this is that after pivotingthe unit (5 and 9) about the main shaft 15 and lifting the granulatecontainer 6 to its upper, open position, wherein its opening plane formssubstantially 90 degrees to the pivot means 21, it will now be possibleto release the bayonet fastening between the cutter 5 and hopper 9.Since the pivot means 21 is now vertically oriented, the hopper 9requires very small force to move it radially about the pivot means 21,which is an important feature of the mill arrangement in accordance withthe invention, and it contributes to the easy and simple openingprocedure.

As will be seen from FIGS. 3 and 4, a high pressure pump 17 is provided,also in the lower portion of the mill 1, for conveying the readycomminuted granulate away from the mill. In order to facilitate serviceand/or cleaning, this pump is also pivotable laterally before tippingthe unit (5 and 9) about the shaft 15 and releasing the bayonetfastening between components 5 and 9. For this purpose the pump isprovided with a hose connection means, which includes a spring-loaded,compressible connector 24 on the first hose 18, the other end of whichhas in turn such a connector 25 for mating with a connection means atthe bottom portion 19 of the container 6. At the other side of thebottom portion 19 there is a similar connection means including aconnector 26 on a second hose 20, which is for conveying readycomminuted granulate away from the container. The cutter drive is from amotor 27 via V-belts 28. Rubber dampers 31 are placed under the mainshaft bearings 16 to prevent transmission of vibrations from the cutter5 to the main frame 4 and further to the substructure supporting themill 1. Noise from the mill is mitigated with the aid of a soundinsulating casing (not illustrated on the drawing). This casingpreferably comprises two halves with mutual hingeing and adapted such asto be pivotable on the main frame 4. The halves are also arranged sothat when they are opened safety switches are operated for interruptingcurrent supply to the electrical components of the mill.

Opening the mill 1, provided with the inventive arrangement, isperformed in the following manner: The first step is to unlatch thesound insulating casing halves, thus interrupting electrical supply tothe mill, and then swing the halves clear. The second step is to releasea lock on the pump and swing it to one side. The third step is torelease the bayonet catch locking the granulate container 6 to thecutter 5, and then to swing the unit formed by the chief mill components5, 6 and 9 about the main pivot shaft 15 through approximately 90degrees to the open position of the mill. During this pivoting orswinging movement, the granulate container 6 is automatically raisedsimultaneously as its plane of opening maintains a substantiallyhorizontal orientation along the line 23 of opening as the containerbecomes completely open. The pivot means 21 on the hopper 9 is now in asubstantially vertical position and preferably at an angle ofapproximately 90 degrees to the line 23 of opening of the container 6.The fourth step is now taken in this completely pivoted position, namelyto release the bayonet catch keeping the hopper 9 to the cutter means,thus enabling the hopper readily to be swung to one side. After serviceand/or cleaning the reverse procedure is performed for returning thecompletely opened mill to its operational state, subsequent to which themill can function once again.

We claim:
 1. A granulating mill, comprising: a cutter disposed forrotation in a granulate container, a collection hopper having a feedopening for supplying to the granulate container pieces of material tobe comminuted, shaft ends of said cutter being rotatably mounted on acentrally disposed subframe, said subframe being pivotably mounted on amain pivot shaft which is mounted on a main frame of the granulatingmill, a high pressure pump being provided for generating an air streamto convey ready comminuted granulate out from the granulate container,the cutter, collection hopper and granulate container being hingedlyconnected to each other via first and second pivot means, and thecutter, collection hopper and granulate container being pivotable aboutthe main shaft via the central subframe carrying the cutter, wherein aline of action of a common center of gravity of the cutter, collectionhopper and granulate container, substantially passing through said mainshaft such that said cutter, collection hopper and granulate containerare statically balanced about it, thereby requiring only minor force topivot the cutter, collection hopper and granulate container intoposition for opening the mill for service and/or cleaning.
 2. Thegranulating mill as claimed in claim 1, wherein the second pivot meansbetween the cutter and granulate container extends parallel to the mainshaft, such that when a unit including the cutter and collection hopperis pivoted about the main shaft a lower portion of the granulating mill,including the granulate container, which is carried by the second pivotmeans, is simultaneously opened such that at its upper edge forming anopening plane along an opening line of the granulate container israisable from a lower, closed position to an upper, opened position. 3.The granulating mill as claimed in claim 2, wherein the first pivotmeans between the cutter and collection hopper extends transverse to themain shaft, and the cutter is adapted to be swung to one side to open anupper part of the granulating mill, after pivoting or swinging a unitincluding the cutter and collection hopper about the main shaft to anopen position while simultaneously lifting the granulate container toits upper, open position where an opening plane forming an opening lineis substantially at right angles to the first pivot means.
 4. Thegranulating mill as claimed in claim 1, wherein the first pivot meansbetween the cutter and collection hopper extends transverse to the mainshaft, and the cutter is adapted to be swung to one side to open anupper part of the granulating mill, after pivoting or swinging a unit,including the cutter and collection hopper about the main shaft to anopen position while simultaneously lifting the granulate container to anupper, open position where an opening plane forming an opening line issubstantially at right angles to the first pivot means.
 5. Thegranulating mill as claimed in claim 1, wherein before the cutter andcollection hopper of the granulating mill are swung about the main shaftinto an open position, the high pressure pump is adapted to be swung toone side and is engageable with first connection means at an end of afirst hose for supplying air to a lower portion of the granulatecontainer, the first hose is provided with a second connection means atits other end for connection to the lower portion of the granulatecontainer, and a second hose for conveying ready comminuted granulateaway from the granulating mill is connected by a third connection meansto the lower portion of the granulate container.
 6. The granulating millas claimed in claim 5, wherein said first, second and third connectionmeans are spring-loaded and compressible.